Re: Windows Cmd.exe Window
Giles, you keep mentioning syntax errors as the (/a) cause of the problem. I suggest you avoid such problems, so that the import sethook approach, et al. will actually work. The easiest thing to do is to run PyChecker on your script prior to executing it. PyChecker will catch your syntax errors (and a whole host of other things, some of which are actual problems, some not) and let you know where they are. With that simple bit of testing, the other approaches that rely on a syntactically-correct script will work, because you will have corrected the syntax errors. You *will* have corrected the syntax errors, right? :) -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
* Giles Brown (2005-07-07 13:56 +0100)
For my sins I'm a MS Windows user at work and apart from that I have a
small problem ...
I like to write python scripts to do small tasks and then double click
on them from the file explorer to run them.
Unfortunately I'm not perfect and sometimes I make mistakes and have
unhandled exceptions or syntax errors when running the scripts. The
default behaviour is to shut down the command window which leaves you
no chance of reading the exception.
In the past I have created .bat wrapper files that just call the python
interpreter, but it is a bit tedious to have to create a matching .bat
file for every script. So I came up with the following approach...
1. Copy python.exe to pythoncmd.exe
2. Add a bit of stuff to sitecustomize.py
3. Add a special first line to every python script and give it a .cmd
extension.
The stuff added to sitecustomize.py (actually I created a
sitecustomize.py for this) is:
import sys
import os
if os.path.basename(sys.executable) == 'pythoncmd.exe':
def cmdexcepthook(*args):
sys.__excepthook__(*args)
# Let use confirm/inspect error
os.system('pause')
sys.excepthook = cmdexcepthook
The special first line is:
@pythoncmd -x %~f0 %* exit /b
(In the python.org FAQ for windows it says
@setlocal enableextensions python -x %~f0 %* goto :EOF
but since I have no idea which is right I chose the simpler looking
one)
This approach does require pythoncmd.exe to by in your %PATH% but I
think that is reasonable ;)
I am a bit disappointed I couldn't think of a way of deciding if I was
running a .cmd file in sitecustomize.py so that I could just use the
normal python.exe. Using a renamed interpreter .exe is just a trick
for detecting when I am running .cmd files, but it means that the
script won't run on another machine that hasn't had the python.exe
copied to pythoncmd.exe on it. Which is a shame.
So my question. Is there a better way? I'm not really happy with this
approach. Should I stop worrying and go and play my new ukulele?
Answers please.
I think it's a FAQ to: use raw_input at the end to prevent closing.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Nah. You're missing my point. I only want the command window not to be closed if there is an *exception*. Picky I know, but there you go. Giles -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
On 07.07.2005, at 15:25, Giles Brown wrote: Nah. You're missing my point. I only want the command window not to be closed if there is an *exception*. Picky I know, but there you go. well, then register raw_input as exit function: import atexit atexit.register(raw_input) works fine in my terminal. should do in your framework also. cheers, - harold - -- What is mind? -- Doesn't matter. What is matter? -- Never mind! -- -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
On 07.07.2005, at 15:43, harold fellermann wrote: On 07.07.2005, at 15:25, Giles Brown wrote: Nah. You're missing my point. I only want the command window not to be closed if there is an *exception*. Picky I know, but there you go. well, then register raw_input as exit function: import atexit atexit.register(raw_input) works fine in my terminal. should do in your framework also. sorry, I did not think. if you want to wait for input _only_ if an exception occured, your exit function needs to check for the exception: import atexit def wait_on_exc() : ... import sys ... if sys.exc_type : ... raw_input() ... atexit.register(wait_on_exc) this should do the job, now. - harold - -- What if nothing exists and everything is an illusion? In this case I definitely overpayed my new carpet! -- Woody Allen -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Use sys.excepthook to hook a function you define and in that function
print a traceback and pause before exiting. Something like (not tested
but copied from working example):
import sys
def Myexcepthook(type, value, traceback):
print in Myexcepthook-type=, type, value=,value, traceback=,traceback
import traceback
lines=traceback.format_exception(type, value, traceback)
print -Traceback lines---
print \n.join(lines)
print ---
t=raw_input(Press return to continue)
sys.exit(2)
#
# set sys.excepthook
#
sys.excepthook=Myexcepthook
#
# create an uncaught divide by zero exception
#
a=1/0
-Larry Bates
Giles Brown wrote:
For my sins I'm a MS Windows user at work and apart from that I have a
small problem ...
I like to write python scripts to do small tasks and then double click
on them from the file explorer to run them.
Unfortunately I'm not perfect and sometimes I make mistakes and have
unhandled exceptions or syntax errors when running the scripts. The
default behaviour is to shut down the command window which leaves you
no chance of reading the exception.
In the past I have created .bat wrapper files that just call the python
interpreter, but it is a bit tedious to have to create a matching .bat
file for every script. So I came up with the following approach...
1. Copy python.exe to pythoncmd.exe
2. Add a bit of stuff to sitecustomize.py
3. Add a special first line to every python script and give it a .cmd
extension.
The stuff added to sitecustomize.py (actually I created a
sitecustomize.py for this) is:
import sys
import os
if os.path.basename(sys.executable) == 'pythoncmd.exe':
def cmdexcepthook(*args):
sys.__excepthook__(*args)
# Let use confirm/inspect error
os.system('pause')
sys.excepthook = cmdexcepthook
The special first line is:
@pythoncmd -x %~f0 %* exit /b
(In the python.org FAQ for windows it says
@setlocal enableextensions python -x %~f0 %* goto :EOF
but since I have no idea which is right I chose the simpler looking
one)
This approach does require pythoncmd.exe to by in your %PATH% but I
think that is reasonable ;)
I am a bit disappointed I couldn't think of a way of deciding if I was
running a .cmd file in sitecustomize.py so that I could just use the
normal python.exe. Using a renamed interpreter .exe is just a trick
for detecting when I am running .cmd files, but it means that the
script won't run on another machine that hasn't had the python.exe
copied to pythoncmd.exe on it. Which is a shame.
So my question. Is there a better way? I'm not really happy with this
approach. Should I stop worrying and go and play my new ukulele?
Answers please.
Giles
--
http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Thanks for your replies.
I think we might have a miscommunication here as (to my understanding)
neither of your replies actually solve my problem.
After all, the function raw_input is just another way of blocking until
user input. I was already doing that using os.system('pause').
To recap, what I'm looking for is a way of setting up specific scripts
(not every script) so that when I double click on it, it runs, but if
there is an exception (even a SyntaxError in the top level script) I
get a traceback in a window that doesn't disappear immediately.
The tricky elements of this are:
1) It can't be done using code in the script itself (such as using an
import statement) because in the presence of a SyntaxError the import
statement is never run. This is why I was looking at sitecustomize.py
2) I don't want to do unusual exception/atexit hooking for every script
and so need to be able to detect when I am running one of these .cmd
type scripts.
I hope this clarifies things. I had hoped that my question was worded
sufficiently well to indicate this wasn't a straight-down-the-line
newbie question (I've been programming in Python for seven years now).
Obviously it wasn't. My apologies.
Giles
--
http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Giles Brown [EMAIL PROTECTED] writes: Nah. You're missing my point. I only want the command window not to be closed if there is an *exception*. Picky I know, but there you go. I find it useful to set an sys.excepthook which calls the debugger pdb.pm(). This way I not only see the traceback, but I can also poke around in the environment to find the problem. Thomas -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Hi Larry, I mentioned how I am already using sys.excepthook in my initial posting. What I'm looking for is: 1) Is there any better way of solving the problem than setting sys.excepthook in sitecustomize.py? 2) Or is there a better way of detecting when I am running a .cmd based script than the method I proposed? Hope this clears up what I'm asking for. Thanks, Giles -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
harold fellermann wrote: sorry, I did not think. if you want to wait for input _only_ if an exception occured, your exit function needs to check for the exception: import atexit def wait_on_exc() : ... import sys ... if sys.exc_type : ... raw_input() ... atexit.register(wait_on_exc) this should do the job, now. Did you think to test your code before posting it? sys.exc_type is deprecated (you should use sys.exc_info() instead), but neither will tell you whether the program is exiting as a result of an exception when called from an atexit function, by the time the atexit function is called the exception is no longer accessible. As Larry Bates suggested, the OP needs to use a sys.excepthook. Unfortunately he doesn't test his code either (the parameter 'traceback' conflicts with the module 'traceback'), but at least the principle is correct. -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Giles Brown wrote: The special first line is: @pythoncmd -x %~f0 %* exit /b (In the python.org FAQ for windows it says @setlocal enableextensions python -x %~f0 %* goto :EOF but since I have no idea which is right I chose the simpler looking one) This approach does require pythoncmd.exe to by in your %PATH% but I think that is reasonable ;) I am a bit disappointed I couldn't think of a way of deciding if I was running a .cmd file in sitecustomize.py so that I could just use the normal python.exe. Using a renamed interpreter .exe is just a trick for detecting when I am running .cmd files, but it means that the script won't run on another machine that hasn't had the python.exe copied to pythoncmd.exe on it. Which is a shame. I'm having problems understanding your problem. If the file is a .cmd file then surely the second line (i.e. the one immediately following the python -x command) could simply do import sethook where sethook would be a module that sets your excepthook. Alternatively you could check at any point whether sys.argv[0] ends with '.cmd' or '.bat' (after lowercasing). So my question. Is there a better way? I'm not really happy with this approach. Should I stop worrying and go and play my new ukulele? Answers please. Go on, upload some ukulele playing somewhere. BTW, another solution is to push the pause command out to the shell: --- @setlocal enableextensions (python -x %~f0 %* || pause) goto :EOF import sys if len(sys.argv) 1: sys.exit(this will pause) --- will pause only if the python program terminates with a non-zero exit code. This means messages from sys.exit will cause a pause as well as exceptions. -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Hooray! We have a winner! Thanks Duncan. Your improved shell line will do the job very nicely. :) (btw, the problem with import sethook at the top of the script is that syntax errors in the top-level will prevent the import from being run meaning we don't get our traceback anymore.) Giles -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
Addendum - forgot to mention that the problem with checking the extension of sys.argv[0] is that sys.argv[0] is not set until after sitecustomize.py is run (and it needs to be in sitecustomize.py not an imported module due to the top-level SyntaxError problem mentioned in my other post). Cheers again for your elegant solution. Giles -- http://mail.python.org/mailman/listinfo/python-list
Re: Windows Cmd.exe Window
In the past I have created .bat wrapper files that just call the python interpreter, but it is a bit tedious to have to create a matching .bat file for every script. So I came up with the following approach... I frequently use a batch file wrapper. Typically it has a long friendly name for others in my (non-IT) department, and calls the actual python script in a subfolder, often with arguments. The last line of the batch file is usually a pause command. As an alternative, I have a couple of main procedures wrap a try/except around the entire script, and if an error occurs, then logs the details before quitting. I suppose you could also print the error, and add a call raw_input() so its visible before the window closes. Hope that helps, Brian. -- http://mail.python.org/mailman/listinfo/python-list
